Tank gauge with remote indicator



July 2, 1957 J. F. WILHELM TANK GAUGE WITH REMOTE INDICATOR Filed May 14. 1954 uobonraoeosooaoononnle United States Patent() "ice 2797577 t Patented July 2, 1957Y which the operator filling the tank should stop pouring liquid into the inlet pipe. This should be done a little 2 797 57,7 bit before the indicator shows that the tank is full, be-

TANK GAUGE .WIGTH REMOTE INDICATR Joseph F. Wilhelm, Green Bay, Wis., assignor to Krueger Sentry Gauge Company, Green Bay, Wis., a corporation of Wisconsin Application May 14, 1954, Serial No. 429,789

2 Claims. (Cl. 73-318) My invention relates to gauges and includes among its objects and advantages increased cheapness in manufacture and installation, in the type rof gauge in which the indication is mechanically transmitted to a remote point.

In the accompanying drawings:

Figure l is a partly diagrammatic View of a complete installation employing a gauge according to the invention;

Figure 2 is an enlarged section of the external indicator and part of the transmission to it;

Figure.3 is an elevation ofthe externally projecting portion of the indicator of Figure 2; l

Figure 4 is an end view of the indicator; and

Figure 5 isa section of the end of the transmission next to the tank. v

In the embodiment selectedto illustrate the invention, the conventional fuel tank is shown mounted on supporting legs 12 in the basement of a building having a concrete basement Wall 14 and a wooden wall 16 above the concrete wall. The actuating mechanism includes a standard 18, a float arm 20 pivoted to the lower end of the standard, and a pitman 22. These parts are conventional and may be as illustrated in my earlier Patent 2,580,057, issued December 25, 1951. The plug 24 is also generally similar to that of my earlier patent. It has a polygonal portion 26 for screwing it in place, and pipe threads 28 for mounting it in the tank. By providing it also with machine threads at 30 andra rabbetk at 32, the same plug may be used for assembly with the external indicator parts described in my prior patent.

When associated with a transmission according to the invention, the plug is centrally bored and internally threaded to receive a short section of pipe 36, functioning as a mechanical guide for the coupling member 38, threaded on the end of the pitman 22. The transmission chain 40 is of the flexible ball and pin type conventional in the art. The end ball 42 is positioned inside the coupling 38, after which the end of the coupling is swedged in, as indicated at 44, to complete the assembly. The tube 36 is long enough so that the coupling 38 remains inside it throughout the range of movement of the parts.

At the opposite end of the chain I provide indicator means comprising a tubular housing 46, carrying an escutcheon ring 48, which is brazed or pressed on the tube 46. The tube 46 projects beyond the escutcheon plate and is externally threaded at 50 to receive a cap. The cap is a cylindrical tube with opposite windows at 52 and 54, and is formed of two pieces of sheet metal Sl and 53, each stamped to define a semi-circle with laterally projecting anges at both sides. The anges are spot welded together and carry indicia inscribed or aflixed thereto.

As clearly indicated in Figure 3, the indicia include the capital letter E at 56 and the capital letter F at 58 and intermediate indicia for reading the amount of iluid in the tank. When associated with a storage tank for fuel for house heating, or any similar service, it is convenient to have special indicia indicating the point at cause the contents of the tube will continue to run down into the tank after the operator turns oil? the nozzle. Generally similar installations now in use have to depend on the operators judgment in that connection, and judgment by the operator is as useful as ever, but the additional indication is a convenience to a careful operator, if properly designed to allowfor the colume of the inlet pipe, as indicated at 59.

Inside the tube 46 I provide a transparent plastic tube 60, which defines a hermetically sealed enclosure by means of a gasket 62 at one end of the tube 46 and a cooperating gasket 64 at the remote end of the cap. The fastening nut 66 in the end of the cap enables the person making the installation tighten up on the gasket and secure a good hermetic seal. Inside the tube is the indilcator member proper, which is a yellow plastic tube 68 having a small central bore 74 just large enough for convenient insertion of the end of the chain 40. VBetween the indicator 68 and the gasket 62, I position-a light spring I70 of sufficient strength to exert a force materially greater than the weight of the chain 40, but still negligible compared with the forces that can be exerted by the pitman In installing the device the operator adjusts the position of the indicator member 68 on the chain 4t) and.

then tightens the set screw 72 to force one or two balls against the remote side of the bore 74. It will be noted that the set screw 72 has a atinner end of sufiicient diameter so that it can engage two adjacent balls of the chain, if that happens to be the desired position of adjustment. Accordingly, there isvno position of the chain lwhere the set screw 72 will not push squarely against at least one ball, and because of this, continuous adjustment is available to the operator, whereas if theL set screw were pointed or smaller, it would enter between adjacent -balls and force the Voperator to make the best of a step by` .step adjustment.

The chain 40 is guided from the tank 10 to the tubeA l 46 through copper tubing 76 of indefinite length, but all the changes in direction in the copper tubing have a radius of curvature best indicated at the left side of Figure 2, such that a large number of balls in the chain all have contact with the side wall of the tubing, and the change of direction of the tubing, between its contact with successive balls, is extremely small. It is Well known that the tension in a flexible member having friction contact with a stationary element throughout a curved or arcuate path, is increased by the friction according to an exponential equation. Where the lcoefcient of friction is at all large, the transmission of motion tends to become impossible, and the relationship is that of a powerful brake. Thus, it is well known that a hawser from a ship can be wrapped about four times around a bitt on the dock, and a workman only applies a few pounds of tension to the free end of the hawser to develop a tension that will come close to pulling a hawser in two, in the reach of the hawser between the bitt and ship, so that the ship is powerfully snubbed and brought to rest.

Because the conventional steel balls making up the chain 40 have a very low coefficient of friction in Contact with a dissimilar metal, such as copper, and because the radius of curvature of the tubing is always large enough to permit contact at a large number of points with only slight changes of direction between successive points, it is possible to secure an extremely low coefficient of friction combined with contact areas that are extremely small. Also, the balls are harder than the tube, so that the tube develops a shallow groove, rather than wearing at spots on the balls. In this Way the tubing soon acquires a very low.

Such chain is available on the market with ample tensile strength for the service desired, but weighing only a few ounces for a hundred feet. One grade that has been often satisfactory has a breaking point of twenty-six pounds and weighs only one pound per one hundred fortysix feet of chain length. By using a spring 70 which exerts a tension of only two to four ounces greater than the weight of that portion of the chainwhich occupies a vertical position, experience has demonstrated that installations can function very successfully with as many as six or eight right angle turns, when needed to carry a chain from the tank to the point where the external indication is desired, and with a length of chain as great as fifty feetl or more. Obviously, very few installations will call for such extreme conditions, but tests have shownthat such service can be achieved dependably with the construction disclosed.

I am at present unable to state what the angle `subtend by two successive balls in a curved tube should be, but excellent results are obtainable with an angle of three degrees, and I believe the angle should not exceed six degrees, to secure the long wear and low frictionA characteristic of the invention. i

Also, the.diameter of the ball is about one-fifth the inside diameter of the tube. The ball must be'large enough so that the contact area willcarry the lateral pressure in pure sliding, without gouging or machining the material of the tube. lThis is essential `to developA a polishing action during use, as` distinguished from abrasion.` A contact member of the much smaller diameter of the pins connecting the balls would be flexible enough, but before long it would wear a groove deep enough to wedge itself in the groove and renderV the de` of the novel features disclosed or equivalents thereof. As at present advised with respect to the apparent scope of my invention, I desire to claim the following subject matter:

1. In a remote reading gauge, in combination: a transparent tube; an opaque tubular indicator member longitudinally slideable in said tube; a flexible tension member for pulling said indicator member in one direction; spring means tending to move said indicator member in the other direction with sufficient force to take up slack in the tension member in all positions; said tension member passing longitudinally through said indicator member;

,said tension member comprising a plurality of inter-connected, uniformly spaced hollow spheres; and a set screw in one side of said indicator member; said set screw having ya flat inner end engaging said tension member; said flat inner end having a diameter not less than the center-to center spacing of said spheres.

2. In a remote reading gauge, in combination: a transparent tube; an opaque tubular indicator member longitudinally slideable in said tube; a exible tension memberl ying said tension member infadjusted position; a fixed housing removably receiving a portion of said transparent tube; and an extension housing mounted on said fixed housing and enclosing the remainder of said transparent tube and retaining saidl transparent tube in place in said fixed housing; said extension housing being removable Ato permit removal of said transparent tube for access to said set screw.

References Cited in the file of this patent UNITED STATES PATENTS France May 15, 1933 

